What is Change?

Something changes if it is different at a different time

What is the logic of the word `different'?

`Different' is a 3-term relation:
x is different from y in respect of A-ness
I am different from you in respect of height, but not in respect of being human, or being interested in time.
When we meet an old friend at a Gaudy, and say that he is unchanged, we mean unchanged in respect of character, sense of humour, . . .
not unchanged in respect of hair-coverage, body shape, income, or marital status.
It is natural to want God to be changeless in the sense of being always reliable, not capricious, trustworthy, not fickle,
but quite unreasonable to require him to be unmoved by our plight, unresponsive to our prayers.
The Absolutely Changeless is unlikely to do its metaphysical work:
in classical materialism the atoms, although always the same in themselves, have different positions and velocities at different times